#include <memory.h>  
#include "md5.h"  
   
unsigned char PADDING[]={0x80,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
						 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
						 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,  
						 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};  
						   
/**
* @brief 
*
* @param context
*/
void MD5Init(MD5_CTX *context)  
{  
	 context->count[0] = 0;  
	 context->count[1] = 0;  
	 context->state[0] = 0x67452301;  
	 context->state[1] = 0xEFCDAB89;  
	 context->state[2] = 0x98BADCFE;  
	 context->state[3] = 0x10325476;  
}  

/**
* @brief 
*
* @param context
* @param input
* @param inputlen
*/
void MD5Update(MD5_CTX *context,unsigned char *input,unsigned int inputlen)  
{  
	unsigned int i = 0,index = 0,partlen = 0;  
	index = (context->count[0] >> 3) & 0x3F;  
	partlen = 64 - index;  
	context->count[0] += inputlen << 3;  
	if(context->count[0] < (inputlen << 3))  
	   context->count[1]++;  
	context->count[1] += inputlen >> 29;  
	  
	if(inputlen >= partlen)  
	{  
	   memcpy(&context->buffer[index],input,partlen);  
	   MD5Transform(context->state,context->buffer);  
	   for(i = partlen;i+64 <= inputlen;i+=64)  
		   MD5Transform(context->state,&input[i]);  
	   index = 0;          
	}    
	else  
	{  
		i = 0;  
	}  
	memcpy(&context->buffer[index],&input[i],inputlen-i);  
}
  
/**
* @brief 
*
* @param context
* @param digest[16]
*/
void MD5Final(MD5_CTX *context,unsigned char digest[16])  
{  
	unsigned int index = 0,padlen = 0;  
	unsigned char bits[8];  
	index = (context->count[0] >> 3) & 0x3F;  
	padlen = (index < 56)?(56-index):(120-index);  
	MD5Encode(bits,context->count,8);  
	MD5Update(context,PADDING,padlen);  
	MD5Update(context,bits,8);  
	MD5Encode(digest,context->state,16);  
}  

/**
* @brief 
*
* @param output
* @param input
* @param len
*/
void MD5Encode(unsigned char *output,unsigned int *input,unsigned int len)  
{  
	unsigned int i = 0,j = 0;  
	while(j < len)  
	{  
		 output[j] = input[i] & 0xFF;    
		 output[j+1] = (input[i] >> 8) & 0xFF;  
		 output[j+2] = (input[i] >> 16) & 0xFF;  
		 output[j+3] = (input[i] >> 24) & 0xFF;  
		 i++;  
		 j+=4;  
	}  
}

  
/**
* @brief 
*
* @param output
* @param input
* @param len
*/
void MD5Decode(unsigned int *output,unsigned char *input,unsigned int len)  
{  
	 unsigned int i = 0,j = 0;  
	 while(j < len)  
	 {  
		   output[i] = (input[j]) |  
					   (input[j+1] << 8) |  
					   (input[j+2] << 16) |  
					   (input[j+3] << 24);  
		   i++;  
		   j+=4;   
	 }  
}  

/**
* @brief 
*
* @param state[4]
* @param block[64]
*/
void MD5Transform(unsigned int state[4],unsigned char block[64])  
{  
	 unsigned int a = state[0];  
	 unsigned int b = state[1];  
	 unsigned int c = state[2];  
	 unsigned int d = state[3];  
	 unsigned int x[64];  
	 MD5Decode(x,block,64);  
	 FF(a, b, c, d, x[ 0], 7, 0xd76aa478); /* 1 */  
 FF(d, a, b, c, x[ 1], 12, 0xe8c7b756); /* 2 */  
 FF(c, d, a, b, x[ 2], 17, 0x242070db); /* 3 */  
 FF(b, c, d, a, x[ 3], 22, 0xc1bdceee); /* 4 */  
 FF(a, b, c, d, x[ 4], 7, 0xf57c0faf); /* 5 */  
 FF(d, a, b, c, x[ 5], 12, 0x4787c62a); /* 6 */  
 FF(c, d, a, b, x[ 6], 17, 0xa8304613); /* 7 */  
 FF(b, c, d, a, x[ 7], 22, 0xfd469501); /* 8 */  
 FF(a, b, c, d, x[ 8], 7, 0x698098d8); /* 9 */  
 FF(d, a, b, c, x[ 9], 12, 0x8b44f7af); /* 10 */  
 FF(c, d, a, b, x[10], 17, 0xffff5bb1); /* 11 */  
 FF(b, c, d, a, x[11], 22, 0x895cd7be); /* 12 */  
 FF(a, b, c, d, x[12], 7, 0x6b901122); /* 13 */  
 FF(d, a, b, c, x[13], 12, 0xfd987193); /* 14 */  
 FF(c, d, a, b, x[14], 17, 0xa679438e); /* 15 */  
 FF(b, c, d, a, x[15], 22, 0x49b40821); /* 16 */  
   
 /* Round 2 */  
 GG(a, b, c, d, x[ 1], 5, 0xf61e2562); /* 17 */  
 GG(d, a, b, c, x[ 6], 9, 0xc040b340); /* 18 */  
 GG(c, d, a, b, x[11], 14, 0x265e5a51); /* 19 */  
 GG(b, c, d, a, x[ 0], 20, 0xe9b6c7aa); /* 20 */  
 GG(a, b, c, d, x[ 5], 5, 0xd62f105d); /* 21 */  
 GG(d, a, b, c, x[10], 9,  0x2441453); /* 22 */  
 GG(c, d, a, b, x[15], 14, 0xd8a1e681); /* 23 */  
 GG(b, c, d, a, x[ 4], 20, 0xe7d3fbc8); /* 24 */  
 GG(a, b, c, d, x[ 9], 5, 0x21e1cde6); /* 25 */  
 GG(d, a, b, c, x[14], 9, 0xc33707d6); /* 26 */  
 GG(c, d, a, b, x[ 3], 14, 0xf4d50d87); /* 27 */  
 GG(b, c, d, a, x[ 8], 20, 0x455a14ed); /* 28 */  
 GG(a, b, c, d, x[13], 5, 0xa9e3e905); /* 29 */  
 GG(d, a, b, c, x[ 2], 9, 0xfcefa3f8); /* 30 */  
 GG(c, d, a, b, x[ 7], 14, 0x676f02d9); /* 31 */  
 GG(b, c, d, a, x[12], 20, 0x8d2a4c8a); /* 32 */  
   
 /* Round 3 */  
 HH(a, b, c, d, x[ 5], 4, 0xfffa3942); /* 33 */  
 HH(d, a, b, c, x[ 8], 11, 0x8771f681); /* 34 */  
 HH(c, d, a, b, x[11], 16, 0x6d9d6122); /* 35 */  
 HH(b, c, d, a, x[14], 23, 0xfde5380c); /* 36 */  
 HH(a, b, c, d, x[ 1], 4, 0xa4beea44); /* 37 */  
 HH(d, a, b, c, x[ 4], 11, 0x4bdecfa9); /* 38 */  
 HH(c, d, a, b, x[ 7], 16, 0xf6bb4b60); /* 39 */  
 HH(b, c, d, a, x[10], 23, 0xbebfbc70); /* 40 */  
 HH(a, b, c, d, x[13], 4, 0x289b7ec6); /* 41 */  
 HH(d, a, b, c, x[ 0], 11, 0xeaa127fa); /* 42 */  
 HH(c, d, a, b, x[ 3], 16, 0xd4ef3085); /* 43 */  
 HH(b, c, d, a, x[ 6], 23,  0x4881d05); /* 44 */  
 HH(a, b, c, d, x[ 9], 4, 0xd9d4d039); /* 45 */  
 HH(d, a, b, c, x[12], 11, 0xe6db99e5); /* 46 */  
 HH(c, d, a, b, x[15], 16, 0x1fa27cf8); /* 47 */  
 HH(b, c, d, a, x[ 2], 23, 0xc4ac5665); /* 48 */  
   
 /* Round 4 */  
 II(a, b, c, d, x[ 0], 6, 0xf4292244); /* 49 */  
 II(d, a, b, c, x[ 7], 10, 0x432aff97); /* 50 */  
 II(c, d, a, b, x[14], 15, 0xab9423a7); /* 51 */  
 II(b, c, d, a, x[ 5], 21, 0xfc93a039); /* 52 */  
 II(a, b, c, d, x[12], 6, 0x655b59c3); /* 53 */  
 II(d, a, b, c, x[ 3], 10, 0x8f0ccc92); /* 54 */  
 II(c, d, a, b, x[10], 15, 0xffeff47d); /* 55 */  
 II(b, c, d, a, x[ 1], 21, 0x85845dd1); /* 56 */  
 II(a, b, c, d, x[ 8], 6, 0x6fa87e4f); /* 57 */  
 II(d, a, b, c, x[15], 10, 0xfe2ce6e0); /* 58 */  
 II(c, d, a, b, x[ 6], 15, 0xa3014314); /* 59 */  
 II(b, c, d, a, x[13], 21, 0x4e0811a1); /* 60 */  
 II(a, b, c, d, x[ 4], 6, 0xf7537e82); /* 61 */  
 II(d, a, b, c, x[11], 10, 0xbd3af235); /* 62 */  
 II(c, d, a, b, x[ 2], 15, 0x2ad7d2bb); /* 63 */  
 II(b, c, d, a, x[ 9], 21, 0xeb86d391); /* 64 */  
	 state[0] += a;  
	 state[1] += b;  
	 state[2] += c;  
	 state[3] += d;  
}  
